dart2js cps: Fix for tear-off of noSuchMethod or toString on null.

pkg/compiler/lib/src/cps_ir/optimizers.dart

Index: pkg/compiler/lib/src/cps_ir/optimizers.dart
diff --git a/pkg/compiler/lib/src/cps_ir/optimizers.dart b/pkg/compiler/lib/src/cps_ir/optimizers.dart
index 45606ecc86557be7f1080835c501c9c68ed678ab..19227ad6c51b2b4d287aaaf9e6d2dc6bc3d064e9 100644
--- a/pkg/compiler/lib/src/cps_ir/optimizers.dart
+++ b/pkg/compiler/lib/src/cps_ir/optimizers.dart
@@ -54,7 +54,8 @@ bool isTruthyConstant(ConstantValue value, {bool strict: false}) {
   return strict ? value.isTrue : !isFalsyConstant(value);
 }
 
-/// Selector that do not throw when invoked on the null class.
+/// Selectors that do not throw when invoked on the null value.
 final List<Selector> selectorsOnNull = <Selector>[
     Selectors.equals, Selectors.hashCode_, Selectors.runtimeType_,
-    Selectors.toString_];
+    Selectors.toString_, Selectors.toStringGetter,
+    Selectors.noSuchMethodGetter];